In all types of wedge gate valve body processing, usually exist in the wedge angle of 2 ° 5 'of the wedge machining M85 × 2-6H thread problem. In order to improve work efficiency, a special tool to complete the installation of two oblique wedge on the surface of the screw machining tooling, shown in Figure 2. 1. Workpiece Design (1) Workpiece Analysis Workpieces of this type have symmetry. If the work piece is rotated by 180 ° around the axis O1'O2 'with an offset of e, the center O2 of the right-hand thread is at the centerline of the original left-hand thread O1O extension line, and the right end of the screw thread perpendicular to the left end of the thread center line O1O, that is, with the original left end of the thread parallel to the end face. (2) Design Requirements It can be known from the analysis of the workpiece that once the clamping process is completed, the left-hand thread center O1 must be on the centerline of the lathe spindle and the thread end face should be perpendicular to the spindle centerline ; In the processing of the right-hand thread, the workpiece must be rotated 180 ° on the fixture, right-hand thread center O2 after rotation must also be in the lathe spindle centerline, and the thread end face perpendicular to the spindle centerline. (3) Structural features There is a T-shaped groove on the carcass 1 for rotation, and the centerline of each revolving dimension at the left end of the carcass is consistent with the centerline of the spindle of the machine tool, so that different conversion flanges can be used to connect with different lathe spindles; The intersection of the centerline of the right end of the carcass and the right end surface of each turn size should be moved upward h such that the intersection of this centerline and the center line of the lathe spindle O is on the centerline of the left- '. To make the left and right ends of the workpiece before and after the rotation of the thread center are lathe spindle center line, the right side of the tire board 3 the size of the center line of rotation should be relative to the left end of the center line of the rotary size downward offset e. (4) Calculation of critical dimensions The center deviation of the rotation dimensions of the left and right ends of the tire tread 3, that is, the offset e = 85 / (2tg2 ° 52 ') of the workpiece rotating around O1'O2'. Carcass 1 left and right ends of the center of rotation height difference h = ltg2 ° 52 '. 2. Clamp installation and application of the fixture with a conversion flange directly connected to the lathe, and CW6163 conversion flange. The use of the flange on the workpiece hole, the workpiece with a nut 12 pressed on the fixture, loosen the nut 5, turn the fixture so that the scale line on the carcass 3 and the scale line on the carcass 1, the positioning pin 15 into the positioning After sleeve 2, tighten the nut 5. In the upper part of the workpiece and the fixture at the top of the same time, the left side of the wedge on the wedge on the thread, if inconsistent, then the car right-hand thread. End processing, parking, loosen the nut 5, the workpiece rotated 180 ° so that the scale on the tire board 3 and the carcass 1 on the scale alignment, positioning pin 15 into the other positioning sleeve, tighten the nut 5 Can cut the other thread. The fixture structure is simple, only need to replace the different tire board, can be used to process similar valves of different sizes. Production practice has proved that the turning tooling easy to use, a fixture can be completed two oblique wedge surface thread processing, can guarantee the quality of the product processing.